The invention concerns sashes and matching frames for windows and glazed doors of which the shaped sections each consists of at least one inner hollow aluminum shaped section and one outer plastic casing.
In prior art frames of this kind the hollow aluminum shaped section is completely enclosed by the plastic casing whereby the aluminum hollow shaped section is covered both with respect to the inside and the outside of the room. Such an arrangement is advantageous in that the hollow aluminum shaped section is not directly exposed to the temperatures either inside or outside the room and accordingly the aluminum hollow shaped section is at a mean temperature whereby excessive shear forces arising from the different thermal expansion coefficients of the two materials are avoided.
However the prior art design suffers from the drawback that the hollow aluminum shaped section--which in the known design extends from the inside to the outside of the room, amounts to a thermal bridge introducing the inside temperature to the outside and vice-versa. The heat insulation which can be achieved by such an arrangement therefore must be unsatisfactory.